1. Field of the Invention
The invention relates to locking devices and, more particularly, to a locking arrangement for a plug apparatus which can be swiveled into an electronic assembly, comprising an unlocking slide which is fastened to the plug apparatus and is in operative connection with a snap hook, which is arranged on a catch.
2. Description of the Related Art
The connection of electronic assemblies, i.e., peripheral assemblies in automation systems, is usually performed by plug apparatuses, i.e., front-panel connectors, which contact the corresponding process via quasi-fixed wiring with the peripherals. Therefore, in the event of an assembly exchange only the front-panel connectors need to be removed and no lines released.
Printed circuit boards, assemblies or plug-in boards for electronic control devices are used advantageously in standardized housings. A sub rack accommodates the assemblies that can be plugged in along guide rails. The assemblies are supplied with electricity or signals through contacts that are attached to either the front side or backwards/sideways. The wiring of the assemblies to each other can also be performed from the reverse side.
The housings have fixed dimensions, serve to accommodate printed circuit boards, and are installed in standardized control cabinets. A housing is composed of two side panels with mounting arms that are connected to each other by four string profiles. The housing is screwed into an electronic cabinet by the two mounting arms.
Plug-in units inserted into the housing, such as printed circuit boards, are controlled by external process signals or are connected to other plug-in units. Connectors, i.e., front-panel connectors comprising push-on terminal strips that are pushed onto the plug-in units from the operating side, are used for this purpose. When selecting the connectors, besides the economy and the required contact pins, above all attention must be paid to the reliability of the connector, mechanical strength, the ability to combine parts supplied by different manufacturers, insulating properties and current load. The connectors generally used for direct connection meet all the requirements for economy and reliability. However, the number of contact pins is often insufficient. The process front panel connector is used above all for peripheral devices if for example, a physical separation of the cables from the internal electronic signal lines is advisable to avoid electrical interference.
The disadvantage of the prior art, however, is that where excess force is used to unlock the plug apparatus from the sub-rack in the event of emergency unlocking, the locking system is often damaged. This results in the plug apparatus and the assembly no longer locking with each other so that this type of unlocking is only possible once.